The “Namespace filters” let you limit your search to changes that happen on particular types of pages or types of files. You can include only the types you’re interested in or you can exclude types that you don’t want to search.

Every page in the wikis is classified into a “namespace” that tells you what type of page it is. For example, user pages are in the “User” namespace; pages of wiki content are in the “Main” namespace; image files and their associated metadata are in the “File” namespace. You can learn more about namespaces on the Help:Namespaces page of MediaWiki.org.

All contents/All discussions: "All contents" and "All discussions" will filter the view to just those namespaces.

However the "All discussions" filter do not include pseudo talk pages, like discussions that are in the Project: or Wikipedia: namespaces. But it will include changes happening on Project talk: or the Wikipedia talk:.

Pick a namespace from the menu: To pick a namespace to filter by, open Namespaces menu and check the box next to that namespace. In the menu, every primary namespace is paired with its associated talk namespace, though these are distinct for searching purposes.[1]

Shortcut—find a namespace by name: If you know the name of a namespace, or a part of it, you can locate it quickly by typing the name into the main filter search bar preceded by a colon. E.g., :template. The menu will display any matches.

Combine namespaces: Select as many namespace filters as you like from the Namespaces menu. Every namespace you add will broaden your search, returning more potential results. (In Boolean terms, namespace filters are joined to one another by OR.)

The namespace "Category" is excluded.

Exclude namespaces: The “Exclude selected” button at the top of the Namespaces menu is useful when you want to search all namespaces except for a few. When you click the “Exclude selected” button, it turns blue to show that you are in Exclude mode. Now, any namespace you select will not be included in your search. To remind you of this, a label next to the namespace in the menu now reads “Excluded,” and in the “Active filters” area above the menu a bold “:not” precedes the namespace label. E.g., “:not Article.”[2] You cannot mix Exclude and Include modes; all your namespaces selections will always be in either one mode or the other.

Use the “Tagged edits” filters to find edits based on whether or not they posses a wide array of properties, each associated with a particular “tag”. Different wikis provide different tags; to see the list of tags available for filtering on your wiki and to learn about how each of them works, go to the Special:Tags page of your wiki.

Tags are pieces of metadata that label edits based on whether or not the edits possess certain defined characteristics. Tags are assigned by programs in the wikis that look at every change as it’s made; if the software finds what it’s looking for, it adds a tag to the metadata about the change. Some tags are simple: they label things like an edit’s source (“mobile app edit”) or identify certain types of edits by straightforward characteristics (“repeating characters”). Other tags are the results of more complex calculations that factor in multiple pieces of information about an edit to make judgements (“possible vandalism”).

Pick a tag from the menu: Tags in the “Tagged edits” filter menu are listed in alphabetical order. Pick the ones you want by checking the boxes next to them.

Shortcut—find a tag by name: if you know the name of a tag (or part of it), you can locate it quickly by typing the tag name into the main filter search bar preceded by #. E.g., #section blanking. The menu will display any matches.

Combine tags: Select as many tag filters as you like from the “Tagged filters” menu. Every tag filter you select will BROADEN your search, returning more potential results. (In Boolean terms, tag filters are joined to one another by OR.)

Coming in later (not scheduled) to the New Filters for Edit Review beta. Categories are not implemented at the moment due to how they are built, and how difficult it is to get actionable results. See the Phabricator task for more information. [1]

Coming in later (not scheduled) to the New Filters for Edit Review beta. That feature hasn't been implanted for now because it requires to have more investigations about a possible use to harass people. [2]

↑The order of the menu is numerical—a fact that will be obvious only to users who know the system, which dictates that every namespace is associated with a number. For example, the “Main” namespace is 0, and the “Main talk” space is 1.